A typical touch screen employs a sheet of glass with a conductive coating, such as indium tin oxide, with four corner terminal connections. The touch screen may be configured as a capacitive or resistive touch screen, with a pattern of electrodes made of conductive material. A finger, stylus, or conductive top sheet can draw or inject current at the point of contact. The current can then distribute to the touch panel terminals in a proportionate manner relative to the location of the point of contact.
Touch detection accuracy of the touch screen can change over time due to a number of system and environmental reasons, such as wear during extended use. Monitoring, testing, and servicing of touch screen systems has conventionally involved manual evaluation of a suspect system by an on-site technician. Such conventional evaluation and repair approaches are both costly and time inefficient. As use of touch screen systems becomes more widespread, particularly in networked applications involving dozens, hundreds, or even thousands of such systems, conventional on-site monitoring, testing, and servicing approaches will become increasingly expensive and less practical to implement.